Paddle type chillers, also known as “rocker chillers,” have a history of use in the poultry processing industry and in other food processing industries. The basic principle of operation is that a paddle or long blade is used to agitate poultry carcasses in a tank of cold heat exchanging liquid to chill the carcasses as the carcasses are advanced by movement of the liquid through the tank.
Continuous introduction of cold water in one end of the tank and removal of warmer water at the other end of the tank provides the mechanism for removing heat from the carcasses and for moving the carcasses along the length of the tank. The side to side rocking motion of a paddle adjacent the semi-cylindrical bottom wall of the tank tends of distribute the carcasses throughout the volume of heat exchanging liquid, thus assuring more thorough contact between the water and the product and more rapid chilling.
An unexpected consequence of paddle type chiller operation has been that carcasses processed in some such chillers retain more moisture than those processed in other types of chillers. Until now, it appears that this moisture retention phenomenon has not been understood or fully exploited. The current invention addresses optimization of moisture retention as well as improving certain operational problems of paddle type chillers.
Moisture retention in the poultry carcasses has significant financial implications for the poultry processing industry. The industry typically measures “yield” of the carcasses as the weight of processed carcasses divided by the live weight of birds delivered to the plant expressed as a percentage. Typical yield for whole carcasses can be around 74%. Processing steps that remove moisture from the meat will reduce yield since the weight of moisture removed is not included in the final product. Use of prior art rocker chillers has been shown to increase yield by about 1%. Use of chillers designed according to the current invention has increased yield by an additional 1% or more. To put this in perspective, a 1% increase in yield at a modest size plant processing 400,000 pounds of poultry per day would generate an additional 5400 pounds of salable product with an additional wholesale value of about $840,000 per year at current prices.